Seasonal patterns of surface inorganic carbon system variables in the Gulf of Mexico inferred from a regional high-resolution ocean biogeochemical model

Fabian A. Gomez, Rik Wanninkhof, Leticia Barbero, Sang Ki Lee, Frank J. Hernandez

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

Uncertainties in carbon chemistry variability still remain large in the Gulf of Mexico (GoM), as data gaps limit our ability to infer basin-wide patterns. Here we configure and validate a regional high-resolution ocean biogeochemical model for the GoM to describe seasonal patterns in surface pressure of CO2 (pCO2), aragonite saturation state (ωAr), and sea-air CO2 flux. Model results indicate that seasonal changes in surface pCO2 are strongly controlled by temperature across most of the GoM basin, except in the vicinity of the Mississippi-Atchafalaya river system delta, where runoff largely controls dissolved inorganic carbon (DIC) and total alkalinity (TA) changes. Our model results also show that seasonal patterns of surface ωAr are driven by seasonal changes in DIC and TA, and reinforced by the seasonal changes in temperature. Simulated sea-air CO2 fluxes are consistent with previous observation-based estimates that show CO2 uptake during winter-spring, and CO2 outgassing during summer-fall. Annually, our model indicates a basinwide mean CO2 uptake of 0.35 molm-2 yr-1, and a northern GoM shelf (< 200 m) uptake of 0.93 molm-2 yr-1. The observation and model-derived patterns of surface pCO2 and CO2 fluxes show good correspondence; thus this study contributes to improved constraints of the carbon budget in the region.

Original languageEnglish (US)
Pages (from-to)1685-1700
Number of pages16
JournalBiogeosciences
Volume17
Issue number6
DOIs
StatePublished - Mar 31 2020

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Earth-Surface Processes

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